Anisotropies in cortical tension reveal the physical basis of polarizing cortical flows
Anisotropies in cortical tension reveal the physical basis of polarizing cortical flows
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DOI：
10.1038/nature09376
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发表时间：
2010-09-01
期刊：
影响因子：
64.8
通讯作者：
Grill, Stephan W.
中科院分区：
文献类型：
--
作者：
Mayer, Mirjam;Depken, Martin;Grill, Stephan W.
不对称的细胞分裂对于多细胞生物的发育是必不可少的。为了继续进行，它们需要一个初始对称的单元格来满足（1）。在秀丽隐杆线虫受精卵中，前后极化由大规模的肌动球蛋白皮质流动促进（2-4），其指导第一次有丝分裂的不对称性。皮质流出现在许多发展背景中（5），但其潜在的力量和物理原理仍然知之甚少。肌动球蛋白收缩性和皮质张力如何相互作用产生大规模血流尚不清楚。在这里，我们报告的亚细胞分布的皮层张力在极化C。线虫受精卵，我们确定使用位置和方向敏感的激光消融。我们证明了皮质流与皮质张力的各向异性相关，并且不受皮质张力梯度的驱动，这与先前的提议相矛盾（5）。这些实验，结合主动皮质力学的理论描述，确定了两个大规模的皮质流的先决条件：在肌动球蛋白收缩力的梯度，以驱动流量和足够大的粘度的皮质，以允许流量是长程的。因此，我们揭示了大规模的细胞内皮层流动，确保有效的极化的C。美丽受精卵
Asymmetric cell divisions are essential for the development of multicellular organisms. To proceed, they require an initially symmetric cell to polarize(1). In Caenorhabditis elegans zygotes, anteroposterior polarization is facilitated by a large-scale flow of the actomyosin cortex(2-4), which directs the asymmetry of the first mitotic division. Cortical flows appear in many contexts of development(5), but their underlying forces and physical principles remain poorly understood. How actomyosin contractility and cortical tension interact to generate large-scale flow is unclear. Here we report on the subcellular distribution of cortical tension in the polarizing C. elegans zygote, which we determined using position- and direction-sensitive laser ablation. We demonstrate that cortical flow is associated with anisotropies in cortical tension and is not driven by gradients in cortical tension, which contradicts previous proposals(5). These experiments, in conjunction with a theoretical description of active cortical mechanics, identify two prerequisites for large-scale cortical flow: a gradient in actomyosin contractility to drive flow and a sufficiently large viscosity of the cortex to allow flow to be long-ranged. We thus reveal the physical requirements of large-scale intracellular cortical flow that ensure the efficient polarization of the C. elegans zygote.